The Treatment Visit will consist of an in-clinic 6-hour observation period. To be eligible for dosing, immediately before dosing subjects must report a baseline score of 4 or greater on the following Numerical Pain Rating Scale (NPRS-NOW) question: "How would you rate your pain RIGHT NOW using a zero to ten scale, where zero equals no pain and ten is the worst pain you can imagine." Qualified subjects will be administered study drug followed by a 6-hour observation in-clinic period. In addition to the Baseline pain intensity assessment conducted just prior to drug administration (Time 0), pain intensity scores (pain right now) will be assessed using the NPRS-NOW at 30 minutes, 1, 2, 3, 4, and 6 hours following study drug administration. Pain relief compared with Baseline will be assessed at those same time points using a 5-point numerical pain relief (NPR) scale, where 0 = no relief, 1 = a little relief, 2 = some relief, 3 = a lot of relief, and 4 = complete relief.